Flexibility of catgut sutures



United States Patent Oflice 2,694,487 Patented. Nov. 16,, 195.4

FLEXIBILITY F CATGUT SUTURES Carl A. Powers, Rose Bay, Sydney, Australia, and Gilbert B. Ayres, Pearl River, N. Y., assignors to Davis & Geek, Inc., Danbury, Conn., a corporation of New York No Drawing. Application August 27, 1953, Serial No. 376,972

8 Claims. (Cl. 206-633) This invention relates to surgical sutures of the proteinaceous type and, more particularly, to the preservation and conditioning of non-boilable surgical sutures. Still more particularly, this invention relates to a method of improving the flexibility of catgut sutures and to the composition of the liquid in which non-boilable catgut sutures are customarily packaged or tubed.

The terms boilable and non-boilable, as applied to proteinaceous sutures in the field of surgery have acquired a highly technical or special meaning. This has come about by reason of the necessity for maintaining the highest degree of sterility and adaptability possible in the production, distribution and use of such sutures. To this end sutures are packaged in hermetically sealed glass tubes together with a preserving or conditioning fluid called tubing fluid. If the tubing fluid used is one that has no deleterious effect on the suture, even at boiling (sterilizing) temperatures, the tube with the suture and fluid inside is labeled boilable. On the other hand, if the tubing fluid used is deleterious to the suture at sterilization temperatures the tube with the suture and fluid inside is labeled non-boilable and referred to as a non-boilable suture.

As tubed, both types of sutures are sterile, but the sealed tube labeled boilable may be subjected to sterilization by heat to prevent danger of contamination by contact of the suture with the outside walls of the tube during removal from the tube while the sealed tube with the suture labeled non-boilable cannot be so sterilized. The terms boilable and non-boilable, as used in surgical practice, further identify the character of the suture itself in that boilable sutures are by their nature hard and stiff upon removal from the tube and must be soaked in water or a suitable conditioning solution before they can be used by the surgeon, whereas non-boilable sutures are soft and pliable and may be used immediately and do not require preliminary softening or soaking.

This is because the protein of which gut is composed is highly reactive and tubing fluids which soften and flexibilize the gut react destructively on the gut at sterilization temperatures. It is, therefore, necessary to use a tubing fluid that is substantially inert toward the gut in the packaging of boilable sutures while the fluid used to tube nonboilable sutures may, and usually does, contain ingredients which not only preserve the suture but also condition it and make it soft and pliable.

The flexibility or pliableness of proteinaceous surgical sutures is important to enable easy and rapid manipulation by the surgeon during an operation. Of the two types of sutures just described, the non-boilable suture, because it can be used immediately upon removal from the ampoule, is by far the more desirable. The packaging of such sutures in two or more sealed, sterile containers, with the ampoule being the innermost container, goes far toward obviating any necessity for boiling the ampoule to sterilize it on the outside before using. However, even non-boilable sutures acquire an undesirable degree of set or kinkiness on standing, particularly if they are of the chrome tanned type and packaged, spirally wound on a spool or spool-type reel, in the ampoule.

It is therefore an object of the present invention to provide a method of improving the flexibility of non-boilable catgut sutures.

A further object of the invention is the provision of an improved tubing fluid composition which shall increase the flexibility of sutures wet therewith over and above that imparted thereto through the use of water, or alcohol and water mixtures alone.

We have: discovered that a small 1 quantity of a-dialkyl phthalate wherrdissolvedr'in any of the usual tubing fluids such as ethyl or isopropyl alcohol; with' the customary quantity 'ofzwater present, actssas a-flexibilizing agent-or plasticizer and substantially improves the pliability and handling of all non-boilable catgut sutures, plain or chromic. This is surprising and unexpected inasmuch as no other plasticizers commonly used for plastics other than gut sutures were found to have any plasticizing effect on such sutures.

Not only do the flexibilizing agents of the present invention improve the pliability and handling of sutures which are otherwise too stiff for use effectively, thus making their use practical, but they appear to return at least some of the flexibility to the suture normally lost during the heat of sterilization before tubing. The presence of our flexibilizing agents enhances the flexibility of the suture over and above that obtainable when only the usual quantity of water is used.

The esters of phthalic acid which have been found to be the most effective are the dialkyl phthalates. Among these may be mentioned the diethyl, dimethyl, dibutyl, di-isoamyl, di-isopropyl and the cicapryl phthalates. Of these the diethyl, dimethyl and dibutyl are the most effective while the use of the diethyl ester is particularly advantageous. These esters which are all colorless liquids are characterized in being nearly insoluble in water but very soluble in alcohols and alcohol-water mixtures of the type commonly used in tubing non-boilable sutures. Concerning the alcohol-water mixtures, the amounts of water ordinarily used varies from 2% to 30%, depending upon the alcohol used, that generally present in ethyl alcohol-water mixtures amounting to from 0.5% to 10% while the water present in a propyl alcohol-water mixture may run as high as 30%, all percentages being by volume. The preferred quantity of dialkyl phthalates used is about 1% by volume of the alcohol or alcohol-water mixture used. Higher concentrations, up to about 5% are compatible with the usual alcohol-water mixtures mentioned to give homogeneous solutions and can be used if desired, but in most instances such high concentration appears to serve no additional purpose. The dialkyl phthalates herein referred to are not injurious to the gut nor are they irritating to tissue with which they come in contact, at the concentrations mentioned.

The tubing fluid compositions of the present invention may be prepared by simply dissolving the requisite quantity of flexibilizing agent in the desired tubing alcohol, or alcohol-water mixture. As stated, the addition of 1% of the agent based on the volume of the total fluid used is a preferred amount but larger quantities may be employed if desired. The fluid containing the agent and the suture is then simply sealed in a container or tube pending use.

We claim:

1. As an article of manufacture, a sealed container having therein, in combination, a proteinaceous suture, a small quantity of a dialkyl phthalate dissolved in a tubing fluid which is substantially non-injurious to the suture at temperatures below sterilization, and water.

2. The subject matter of claim 1 wherein said tubing fluid is a water-soluble, monohydric aliphatic alcohol of from 1 to 4 carbon atoms.

3. The subject matter of claim 1 wherein said tubing fluid is a water-soluble, monohydric aliphatic alcohol of from 1 to 4 carbon atoms containing from 0.5% to 30% by volume of water.

4. As an article of manufacture, a sealed container having therein, in combination, a proteinaceous suture and a homogeneous liquid mixture comprising a major amount of ethyl alcohol and a minor amount each of water and a member of the class consisting of dimethyl phthalate, diethyl phthalate and dibutyl phthalate.

5. As an article of manufacture, a sealed container having therein, in combination, a proteinaceous surgical suture and a liquid mixture comprising by volume from to 98.5% ethyl alcohol, 0.5% to 9% of water and 1% of diethyl phthalate.

6. The method of treating a proteinaceous surgical suture which comprises contacting the suture with a tubing fluid containing dissolved therein a small quantity of a dialkyl phthalate and water to fiexibilize and soften said suture and subsequently sealing the suture in a container.

7. The method of treating proteinaceous surgical sutures which comprises contacting the suture With a tubing fluid containing dissolved therein a small quantity of a dialkyl phthalate and Water and subsequently sealing the suture and the solution in a container.

8. A method of treating proteinaceous surgical sutures which comprises contacting the suture with a solution comprising by volume from 90% to 98.5% ethyl alcohol, 0.5% to 9% of Water and 1% of diethyl phthalate and subsequently sealing the suture and the solution in a con- 5 tainer.

No references cited. 

1. AS AN ARTICLE OF MANUFACTURE, A SEALED CONTAINER HAVING THEREIN, IN COMBINATION, A PROTEINACEOUS SUTURE, A SMALL QUANTITY OF A DIALKYL PHTHALATE DISSOLVED IN A TUBING FLUID WHICH IS SUBSTANTIALLY NON-INJURIOUS TO THE SUTURE AT TEMPERATURES BELOW STERILIZATION, AND WATER. 